If you enjoyed My Father's Dragon you might wish to read the second book in the series Elmer and the Dragon, free download at:
https://epdf.pub/elmer-and-the-dragon2e8500e057f4a65bd2bde210e52901ea33891.html
The Dragons of Blueland finishes off the series. You can find a free download here:
https://epdf.pub/the-dragons-of-bluelandc87d93e47ab096d20490d53df03771d720634.html